JFrame上のJButtonをドラッグしてみる

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RagFrame.java
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/**
$Id: DraggingButtonOnJFrame.html,v 1.1 2009/06/22 16:11:42 kishi Exp kishi $
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;

/**
$Id: DraggingButtonOnJFrame.html,v 1.1 2009/06/22 16:11:42 kishi Exp kishi $
*/

public class RagFrame extends JFrame {
    private int width = 640;
    private int height = 480;

    public RagFrame() {
        super( "JButtonをグラフィックと混在させる" );

        Container contentPane = getContentPane();
        contentPane.setLayout( new FlowLayout() );

        DrawingPanel dp = new DrawingPanel();
        dp.setPreferredSize( new Dimension( width, height ) );

        contentPane.add( dp );
    }

    public static void main( String[] args ) {

        RagFrame frame = new RagFrame();

        /* 終了処理を追加 */
        frame.addWindowListener( new WindowAdapter() {
                                     public void windowClosing( WindowEvent e ) {
                                         System.exit( 0 );
                                     }
                                 }
                               );

        /** サイズと位置を指定 */
        frame.setBounds( 0, 0, frame.width, frame.height );
        frame.setVisible( true );

        frame.pack();

    }
}

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DrawingPanel.java
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import javax.swing.*;

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;

import java.io.*;

/**
$Id: DraggingButtonOnJFrame.html,v 1.1 2009/06/22 16:11:42 kishi Exp kishi $
@author KISHI Yasuhiro
*/

public class DrawingPanel extends JPanel {

    private JButton button;

    public DrawingPanel() {

        // レイアウトマネージャを使用しない
        setLayout( null );

        button = new JButton( "ステップ" );
        button.setBounds( 10, 10, 200, 200 );

        this.add( button );
        button.addMouseMotionListener( new MyMouseMotionListener( ) );

    }

    private class MyMouseMotionListener implements MouseMotionListener {
        public void mouseDragged( MouseEvent argEvent ) {

            System.out.printf( "(%3d,%3d)\n", argEvent.getX() , argEvent.getY() );

            if ( argEvent.getX() < 0 || argEvent.getY() < 0 ) {
                Rectangle objBounds = button.getBounds();

                button.setLocation( objBounds.x + argEvent.getX(), objBounds.y + argEvent.getY() );
            } else {
                Rectangle objBounds = button.getBounds();

                if ( objBounds.x <= objBounds.x + argEvent.getX() && objBounds.x + argEvent.getX() <= objBounds.x + objBounds.width &&
                        objBounds.y <= objBounds.y + argEvent.getY() && objBounds.y + argEvent.getY() <= objBounds.y + objBounds.height ) {

                    button.setLocation( objBounds.x + argEvent.getX(), objBounds.y + argEvent.getY() );
                } else {
                    button.setLocation( argEvent.getX(), argEvent.getY() );
                }
            }

            repaint();
        }

        public void mouseMoved( MouseEvent argEvent ) { }

    }

    /**
    in case when repaint() method is invoked, this method is also executed.
    */
    public void paintComponent( Graphics g ) {

        System.out.println( "paintComponet:" );

        int width = getWidth();
        int height = getHeight();

        // 画面クリア
        g.setColor( Color.black );
        // このコンポーネントのサイズを取得する
        g.fillRect( 0 , 0 , width , height );

        g.setColor( Color.red );
        Point p = button.getLocation();
        g.drawLine( 0, 0, ( int ) p.getX(), ( int ) p.getY() );

    }

}